A current detection circuit for a switching circuit

Abstract

The present invention provides a current detection circuit for a switching circuit, comprising: a switching circuit and a current detection circuit; wherein, the input end of the current detection circuit is electrically connected to the drain of the switching transistor of the switching circuit, and the output end of the current detection circuit is electrically connected to the undervoltage latch module of the switching circuit; the gate of the switching transistor of the switching circuit is driven by an external PWM signal to control the conduction and disconnection of the switching circuit. The present invention detects the current of each switching transistor of the switching circuit through the current detection circuit, and improves the safety of the current detection circuit through the switching transistor current protection module.

Description

Technical Field

[0001] The present invention relates to the technical field of switching circuits, and particularly relates to a current detection circuit for a switching circuit. Background Art

[0002] A switching circuit is a circuit that supplies an external power source to a system. In traditional switching circuits, there is no current detection function. In recent years, with the maturity of technology, some switching circuits are equipped with a current detection circuit. For example, in the patent CN107561343 A, a current detection circuit, a current detection method, and a switching circuit, although the current of the switching circuit is detected by the current detection circuit, the detected current is not processed again to improve the safety of the switching circuit.

[0003] Therefore, after detecting the current of the switching circuit, how to reduce the impact of abnormal current on the switching circuit and improve the accurate value of the current when detecting the current is the direction we need to explore. Summary of the Invention

[0004] The present invention provides a current detection circuit for a switching circuit, which is used to solve the problems of performing different current detections on three switching tubes and protecting the circuit during current detection.

[0005] A current detection circuit for a switching circuit includes: a switching circuit and a current detection circuit; wherein,

[0006] The input end of the current detection circuit is electrically connected to the drain of the switching tube of the switching circuit, and the output end of the current detection circuit is electrically connected to the undervoltage lockout module of the switching circuit;

[0007] The gate of the switching tube of the switching circuit is driven by an external PWM signal to control the conduction and disconnection of the switching circuit.

[0008] As an embodiment of the present invention: the switching circuit includes: a first switching tube, a second switching tube, a third switching tube, an undervoltage lockout module, and an inductor; wherein,

[0009] The input end of the first switching tube is electrically connected to a power source, the output end of the first switching tube is electrically connected to the input end of the inductor, the output end of the inductor is electrically connected to the input end of the third switching tube, the output end of the third switching tube is electrically connected to the input end of the undervoltage lockout module, and the output end of the second switching tube is grounded.

[0010] As an embodiment of the present invention: the switching circuit further includes: a first protection resistor, a second protection resistor, and a third protection resistor; wherein,

[0011] The gate of the first switching transistor is connected to a first protection resistor, and a first PWM driving signal is provided at the input end of the first protection resistor;

[0012] The gate of the second switching transistor is connected to a second protection resistor, and a second PWM driving signal is provided at the input end of the second protection resistor;

[0013] The gate of the third switching transistor is connected to a protection resistor, and a third PWM driving signal is provided at the input end of the third protection resistor.

[0014] As an embodiment of the present invention: The current detection circuit includes:

[0015] A switching transistor current acquisition module, which is used to acquire the currents of the first switching transistor, the second switching transistor and the third switching transistor to obtain real-time current output values; wherein, the current output values include: a first current output value, a second current output value, and a third current output value;

[0016] A switching transistor current detection module: used to perform data analysis on the current output values through the current data space of a current detection chip to obtain abnormal current output values, and determine the source switching transistor through the abnormal current output values; wherein,

[0017] The current data space includes: a characteristic point analysis space of the current output value, an abnormal current data judgment space, and an abnormal current data source tracking space;

[0018] A switching transistor current limiting module: used to adjust the current of the switching transistor when the current detection result is not within a preset current threshold.

[0019] As an embodiment of the present invention: The undervoltage latch module includes:

[0020] A voltage processing unit: used to obtain the output voltage of the switching circuit. When the output voltage is not lower than the output voltage threshold, the undervoltage latch module is in a conducting state. When the output voltage is lower than the output voltage threshold, circuit cutoff latching is performed;

[0021] A circuit latching unit: used to perform a cutoff output voltage on the switching circuit.

[0022] As an embodiment of the present invention: The switching transistor current acquisition module further includes:

[0023] A first switching transistor current acquisition unit: used to generate a first sampling voltage when the current of the first switching transistor passes through a sampling resistor, measure the first sampling voltage value, and obtain the first current output value;

[0024] The second switching transistor current acquisition unit: When the current of the second switching transistor passes through the sampling resistor, it is used to generate a second sampling voltage, measure the second sampling voltage value, and obtain a second current output value;

[0025] The third switching transistor current acquisition unit: When the current of the third switching transistor passes through the sampling resistor, it is used to generate a third sampling voltage, measure the third sampling voltage value, and obtain a third current output value.

[0026] As an embodiment of the present invention: The current detection circuit further includes:

[0027] The switching transistor current protection module: It is used to control the drain voltage of the first switching transistor, the second switching transistor, and the third switching transistor through an operational amplifier, and obtain a stable drain voltage value.

[0028] As an embodiment of the present invention: The switching transistor current detection module further includes:

[0029] The current analysis unit: It is used to set a current analysis program in the current detection chip; wherein the analysis steps of the analysis program are:

[0030] Analysis step one: Analyze the current output value collected in real time through a preset current data space, and analyze the current output value through the data signal characteristics of the current data space;

[0031] Analysis step two: Judge whether each current output value is within a preset fault tolerance range. When the characteristic point of the current output value is within the preset fault tolerance range, classify the current output value as normal data,

[0032] Analysis step three: When the current output value is not within the preset fault tolerance range, classify the current output value as abnormal data;

[0033] The detection abnormal unit: It is used to determine the switching transistor of the abnormal data according to the abnormal data.

[0034] As an embodiment of the present invention: The switching transistor current limiting module further includes:

[0035] The switching transistor overcurrent unit: When the current value of the switching transistor is overcurrent, the switching transistor enters the saturation region, charges the soft start capacitor of the operational amplifier, and consumes the excess current;

[0036] The switching transistor low current unit: When the current value of the switching transistor is lower than the standard current value, the switching transistor enters the non-saturation region, discharges the soft start capacitor of the operational amplifier, and increases the current of the switching transistor.

[0037] As an embodiment of the present invention: The current detection circuit further includes:

[0038] Over-temperature protection module: It is used to detect whether the switching tube is in a high-temperature state by detecting the OTP temperature detection voltage signal. When the temperature of the switching tube exceeds the temperature threshold, the OTP temperature detection voltage signal detects a voltage drop of the switching tube. When the voltage value exceeds the preset minimum voltage value, circuit over-temperature protection is performed to disconnect the switching tube;

[0039] Boost module: It is used to accurately boost the voltage signal of the current acquisition module, boost the output voltage of the current acquisition module through the first boost circuit, and obtain the bias voltage.

[0040] Other features and advantages of the present invention will be described in the subsequent specification, and, in part, will become obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the written specification and the drawings.

[0041] The technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0042] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0043] Figure 1 It is a schematic diagram of the overall circuit of a current detection circuit of a switching circuit in an embodiment of the present invention;

[0044] Figure 2 It is a schematic diagram of the current detection circuit process of a current detection circuit of a switching circuit in an embodiment of the present invention;

[0045] Figure 3 It is a schematic diagram of the switching tube current protection module of the current detection circuit in an embodiment of the present invention. Detailed Embodiments

[0046] The following describes the preferred embodiments of the present invention with reference to the drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0047] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to the other component.

[0048] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0049] In addition, it should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The meaning of "a plurality" is two or more, unless otherwise specifically defined. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0050] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0051] Embodiment 1:

[0052] As Figure 1 shown, an embodiment of the present invention provides a current detection circuit for a switching circuit, including: a switching circuit and a current detection circuit; wherein,

[0053] The input end of the current detection circuit is electrically connected to the drain of the switching transistor of the switching circuit, and the output end of the current detection circuit is electrically connected to the undervoltage lockout module of the switching circuit;

[0054] The gate of the switching transistor of the switching circuit is driven by an external PWM signal to control the conduction and disconnection of the switching circuit.

[0055] In an actual scenario: The switching circuit realizes the current detection of each switching transistor through the on and off of the switching transistor. However, when it is necessary to detect the current of a certain switching transistor, it is necessary to disconnect the other switching transistors, which is inconvenient to operate, and there is no voltage protection and current protection for the circuit either in the switching circuit or in the current detection circuit;

[0056] When implementing the present invention, considering that the output voltage of the switching circuit is likely to fail to reach the preset voltage value and cannot provide a good voltage for the device, an undervoltage latch module is provided on the switching circuit. When the output voltage is lower than the output voltage threshold, the circuit of the switching circuit is latched. The three switching transistors all have independent PWM drive signals for different control modes. When the switching transistor Q1 and the switching transistor Q2 have drive signals at the same time, they constitute an IGBT drive signal. When only one switching transistor has a drive signal, it is a switching transistor circuit to drive the signal of the switching transistor. In the current detection circuit, the switching transistor current acquisition module performs real-time current acquisition on each switching transistor. The switching transistor current detection module is used to perform data analysis and data traceability on the acquired current value. The switching transistor current protection module performs real-time protection on the circuit through an error amplifier and an operational amplifier. The switching transistor current limiting module is used to adjust the current when the switching transistor current is too low or overcurrent to keep the current stable.

[0057] The beneficial effects of the above technical solution are as follows: In the present invention, through the undervoltage latch module, the circuit can be latched when the output voltage is too low to prevent insufficient output voltage when the device needs to be powered. The switching transistor current acquisition module performs real-time acquisition of the output current value of each switching transistor. The IGBT circuit has a better volt-ampere characteristic curve and can be suitable for circuits with a power of more than 600V. When only one has a drive signal, it is suitable for circuits below 600V. The switching transistor current detection module performs real-time analysis and abnormal result traceability on the output current value to determine the source of abnormal data. The switching transistor current limiting module adjusts the overcurrent or too low current to improve the stability of the current. The switching transistor current protection module protects the current detection circuit to improve the safety of the current detection circuit.

[0058] Embodiment 2:

[0059] In one embodiment, the switching circuit includes: a first switching transistor Q1, a second switching transistor Q2, a third switching transistor Q3, an undervoltage latch module, and an inductor L; wherein,

[0060] The input end of the first switching transistor Q1 is electrically connected to the power supply. The output end of the first switching transistor Q1 is electrically connected to the input end of the inductor L. The output end of the inductor L is electrically connected to the input end of the third switching transistor Q3. The output end of the third switching transistor Q3 is electrically connected to the input end of the undervoltage latch module. The output end of the second switching transistor Q2 is grounded.

[0061] In an actual scenario: Generally, a switching circuit has two switching transistors. One switching transistor is connected to the power supply, and the other switching transistor is grounded. By disconnecting one switching transistor to measure the output current value of the other switching transistor, this method cannot perform real-time current acquisition on each switching transistor;

[0062] When the present invention is implemented, considering that there are three switching tubes in the present invention, the input end of the first switching tube Q1 is electrically connected to the power supply, the output end of the second switching tube Q2 is grounded, the input end of the third switching tube Q3 is connected to the inductor L, and the output end of the third switching tube Q3 is electrically connected to the undervoltage lock - in module. The high - and low - level control is performed through the driving signal. When the driving signal is at a high level, the switching tube is in the on state. When the driving signal is at a low level, the switching tube is in the off state. The control of the switching circuit is realized through the on - off of the switching tube.

[0063] The beneficial effects of the above - mentioned technical solution are as follows: The present invention realizes the design of supplying power to the required equipment from an external power supply through the control of three switching tubes. The external power supply provides a stable voltage supply to the required equipment through the first switching tube Q1, the second switching tube Q2, the third switching tube Q3, the inductor L, and the undervoltage lock - in module.

[0064] Embodiment 3:

[0065] In one embodiment, the switching circuit further includes: a first protection resistor R1, a second protection resistor R2, and a third protection resistor R3; where

[0066] The gate of the first switching tube Q1 is connected to the first protection resistor R1, and a first PWM driving signal is set at the input end of the first protection resistor R1;

[0067] The gate of the second switching tube Q2 is connected to the second protection resistor R2, and a second PWM driving signal is set at the input end of the second protection resistor R2;

[0068] The gate of the third switching tube Q3 is connected to the protection resistor R3, and a third PWM driving signal is set at the input end of the third protection resistor R3.

[0069] When the present invention is implemented, over - current protection is performed by connecting a protection resistor to the gate of each switching tube. A PWM driving signal is connected to the input end of the protection resistor, and at the same time, signal control and signal driving of each switching tube can also be performed.

[0070] The beneficial effects of the above - mentioned technical solution are as follows: In the present invention, by connecting a protection resistor to the gate of each switching tube, over - current protection of the switching tube is performed. By connecting the driving signal PWM to the input end of the protection resistor, the signals of each switching tube can be controlled and driven, which is beneficial to improving the safety of the switching circuit.

[0071] Embodiment 4:

[0072] As Figure 2 shown, in one embodiment, the current detection circuit includes:

[0073] A switching transistor current acquisition module, which is used to acquire the currents of the first switching transistor Q1, the second switching transistor Q2, and the third switching transistor Q3 to obtain real-time current output values; wherein, the current output values include: a first current output value, a second current output value, and a third current output value;

[0074] A switching transistor current detection module: used to perform data analysis on the current output values through the current data space of a current detection chip to obtain abnormal current output values, and determine the source switching transistor through the abnormal current output values; wherein,

[0075] The current data space includes: a feature point analysis space of the current output value, an abnormal current data judgment space, and an abnormal current data source tracking space;

[0076] A switching transistor current limiting module: used to adjust the current of the switching transistor when the current detection result is not within the preset current threshold.

[0077] In an actual scenario: the current detection circuit realizes the energization of one switching transistor by disconnecting other switching transistors, acquires the current acquisition signal of this switching transistor, and performs current signal acquisition on each switching transistor in the same way one by one. However, this method cannot acquire the currents of all switching transistors at the same time, and the time required to acquire the current values of a group of switching transistors is too long, and the implementation function of the current detection circuit is too few;

[0078] When implementing the present invention, considering that it is necessary to detect the currents of all switching transistors of the switching circuit, therefore, in the switching transistor current acquisition module, the currents of the switching transistors are acquired through acquisition resistors to obtain the current output values of each switching transistor. In the switching transistor current detection module, the feature analysis of the current output values is realized through the feature point analysis space of the current output value, the abnormal current data judgment space, and the abnormal current data source tracking space, and data abnormality judgment is performed according to the feature points. When it is determined that the data is abnormal data, it is further determined whether the abnormal data is overcurrent data or current-too-low data, and current protection is performed by the method of charging and discharging a soft-start capacitor.

[0079] The beneficial effects of the above technical solution are: in the present invention, the currents of all switching transistors of the switching circuit are simultaneously acquired through the switching transistor current acquisition module, saving the current acquisition time. The switching transistor current detection module can quickly determine abnormal data, perform data analysis and tracking on the abnormal data, and can quickly process the abnormal current data, improving the safety of the switching circuit.

[0080] Embodiment 5:

[0081] In one embodiment, the undervoltage latch module includes:

[0082] Voltage processing unit: used to obtain the output voltage of the switching circuit. When the output voltage is not lower than the output voltage threshold, the undervoltage latch module is in the conducting state. When the output voltage is lower than the output voltage threshold, circuit cutoff latching is performed.

[0083] Circuit latching unit: used to perform a cutoff output voltage on the switching circuit.

[0084] In an actual scenario: In a switching circuit, generally there are only switching transistors and an inductor L. Power supply is carried out by controlling the closing of each switching transistor. However, the input voltage and output voltage of the switching circuit may be unstable according to different external power supplies, which may lead to the situation of undervoltage of the output voltage. But the switching circuit does not have an undervoltage latch module.

[0085] When implementing the present invention, considering that the input voltage and output voltage may be unstable according to different external power supplies, which may lead to the situation of undervoltage of the output voltage, an undervoltage latch module is set for the switching circuit. When the output voltage is lower than the output voltage threshold, circuit latching is performed.

[0086] The beneficial effects of the above technical solution are: In the present invention, by setting up an undervoltage latch module in the switching circuit to perform undervoltage protection on the switching circuit, when the output voltage is lower than the output voltage threshold, circuit latching is performed to avoid damage to the power supply device.

[0087] Embodiment 6:

[0088] In one embodiment, the switching transistor current acquisition module further includes:

[0089] First switching transistor current acquisition unit: used to generate a first sampling voltage when the current of the first switching transistor Q1 passes through the sampling resistor, measure the first sampling voltage value, and obtain a first current output value.

[0090] Second switching transistor current acquisition unit: used to generate a second sampling voltage when the current of the second switching transistor Q2 passes through the sampling resistor, measure the second sampling voltage value, and obtain a second current output value.

[0091] Third switching transistor current acquisition unit: used to generate a third sampling voltage when the current of the third switching transistor Q3 passes through the sampling resistor, measure the third sampling voltage value, and obtain a third current output value.

[0092] In an actual scenario: By sampling the current of one of the switching transistors to obtain a current sampling signal, and generating a current comparison signal from the current sampling signal, and then turning off the switching transistor and turning on the next switching transistor for current sampling, this method cannot sample the currents of all switching transistors simultaneously.

[0093] When the present invention is implemented, considering that in the actual scenario, when sampling the current of the switching tube, there is a lack of real-time performance and simultaneous current acquisition cannot be performed. In this solution, when the current of the switching tube passes through the sampling resistor, a sampling voltage is generated, the sampling voltage value is measured, and the current output value is obtained. The current output value is the current sampling value.

[0094] The beneficial effects of the above technical solution are as follows: In the present invention, when the current of the switching tube passes through the sampling resistor, a sampling voltage is generated, the sampling voltage value is measured, and the current sampling value is obtained. Through this current sampling method, not only can the current of each switching tube be sampled simultaneously, but also the current output value of each switching tube can be sampled in real time.

[0095] Embodiment 7:

[0096] As Figure 3 shown, in one embodiment, the current detection circuit further includes:

[0097] Switching tube current protection module: used to control the drain voltage of the first switching tube Q1, the second switching tube Q2, and the third switching tube Q3 through a buffer to obtain a stable drain voltage value.

[0098] In an actual scenario: The current detection circuit needs to detect the current of each switching tube. In the switching circuit, due to the unstable external power supply, the input voltage is also unstable, and an overvoltage situation of the input voltage occurs;

[0099] When the present invention is implemented, the drain of each switching tube is controlled through the buffer on the switching tube current protection module to stabilize the drain voltage of each switching tube and regulate the drain voltage.

[0100] The beneficial effects of the above technical solution are as follows: In the present invention, the switching tube is controlled to conduct and cut off through the buffer to obtain a stable drain voltage value and protect the circuit.

[0101] Embodiment 8:

[0102] In one embodiment, the switching tube current detection module further includes:

[0103] Current analysis unit: used to set a current analysis program in the current detection chip; wherein the analysis steps of the analysis program are as follows:

[0104] Analysis step one: Analyze the real-time collected current output value through a preset current data space, and analyze the current output value through the data signal characteristics of the current data space;

[0105] Analysis step two: Judge whether each current output value is within the preset fault tolerance range. When the characteristic point of the current output value is within the preset fault tolerance range, classify the current output value as normal data.

[0106] Analysis step three: When the current output value is not within the preset fault tolerance range, classify the current output value as abnormal data;

[0107] Abnormality detection unit: used to determine the switching transistor of the abnormal data according to the abnormal data.

[0108] In an actual scenario: In a current detection circuit, an idle duration control signal is generated through a current signal to determine the idle time, without judging based on the collected current output value, nor judging whether the collected current output value exceeds the preset current output value;

[0109] When implementing the present invention, considering that it is necessary to judge and analyze the collected current output value, a current analysis program is set in the current detection chip of the switching transistor current detection module, and the current output value is analyzed through the data signal characteristics in the preset current data space in the middle, to judge whether the current output value is within the preset fault tolerance range. Through this method, all current output values are classified to determine abnormal data, and the abnormal data is tracked by data return in the abnormality detection unit to determine the data source.

[0110] The beneficial effect of the above technical solution is: In the present invention, the current output value is analyzed through the data signal characteristics in the preset current data space in the current analysis unit, and all current output values can be quickly processed to determine abnormal data.

[0111] Example 9:

[0112] In an embodiment, the switching transistor current limiting module further includes:

[0113] Switching transistor overcurrent unit: used to make the switching transistor enter the saturation region when the current value of the switching transistor is overcurrent, charge the soft start capacitor of the operational amplifier, and consume the excess current;

[0114] Switching transistor low current unit: used to make the switching transistor enter the non-saturation region when the current value of the switching transistor is lower than the standard current value, discharge the soft start capacitor of the operational amplifier, and increase the current of the switching transistor.

[0115] In an actual scenario: In a current detection circuit, there is usually a switching transistor overcurrent protection circuit. When it is detected that the current of the switching transistor exceeds the maximum current value, the excess current value is quickly discharged through an NMOS transistor, but there is no switching current low protection circuit;

[0116] When implementing the present invention, considering that the switch tube current has both overcurrent and low current situations, a switch tube overcurrent unit is set. When the switch tube enters the saturation region, the drain of the switch tube is connected to the soft start capacitor of the operational amplifier for charging to consume the excess current. In the switch tube low current unit, the switch tube enters the non-saturation state, and the soft start capacitor is electrically connected to the gate of the switch tube to increase the current of the switch tube.

[0117] The beneficial effects of the above technical solution are as follows: In the present invention, by setting a switch tube overcurrent unit and a switch tube low current unit, the abnormal current value of the switch tube is adjusted accordingly, so that the current value of the switch tube reaches the normal value.

[0118] As an embodiment of this technical solution, in the case of switch tube overcurrent, the switch tube enters the saturation region, the soft start capacitance is calculated. When the soft start capacitor is not fully charged, the start capacitor connected to the drain of the switch tube is charged to consume the excess current;

[0119] Step 1: Calculate the soft start capacitance:

[0120]

[0121] where C X represents the electric charge stored in the soft start capacitor, C G represents the covering capacitor of the operational amplifier, δ represents the soft start current gain, and D represents the input conductance;

[0122] Step 2: When the electric charge stored in the soft start capacitor exceeds the preset maximum stored electric charge, discharge the soft start capacitor:

[0123] C X >C U

[0124] where the C U is the preset maximum stored electric charge of the soft start capacitor,

[0125] The working principle of the above technical solution is as follows: In this technical solution, when the current value of the switch tube is overcurrent, by setting a soft start capacitor in the switch tube current limiting module, charging and discharging are performed to provide information for switch tube current protection. When the switch tube is overcurrent, overcurrent protection is started. First, since the start capacitor is in the operational amplifier, the electric charge stored in the soft start capacitor is calculated through the covering capacitor of the operational amplifier and the current gain of the soft start itself, and the real-time stored electric charge of the soft start capacitor is obtained. When it is detected that the real-time stored electric charge of the soft start capacitor exceeds the preset maximum stored electric charge of the soft start capacitor, a discharge operation is performed on the soft start capacitor.

[0126] The beneficial effects of the above technical solution are as follows: In the present invention, in the switching transistor overcurrent unit, when the current of the switching transistor is overcurrent, the real-time charge of the soft-start capacitor is first calculated. By calculating the real-time charge of the soft-start capacitor, when the real-time stored charge amount of the soft-start capacitor exceeds the preset maximum stored charge amount, the soft-start capacitor is discharged to prevent the dielectric of the soft-start capacitor from being broken down when performing switching transistor current protection.

[0127] Embodiment 10:

[0128] In one embodiment, the current detection circuit further includes:

[0129] Over-temperature protection module: used to detect whether the switching transistor is in a high-temperature state by the OTP temperature detection voltage signal. When the temperature of the switching transistor exceeds the temperature threshold, the OTP temperature detection voltage signal detects a voltage drop of the switching transistor. When the voltage value exceeds the preset minimum voltage value, circuit over-temperature protection is performed to disconnect the switching transistor;

[0130] Boost module: used to accurately boost the voltage signal of the current acquisition module, boost the output voltage of the current acquisition module through the first boost circuit, and obtain the bias voltage.

[0131] In an actual scenario: The current detection circuit detects the current of the switching transistor in the switching circuit. The circuit is mostly a simple circuit and can achieve the basic functions of the current detection circuit. However, as the input voltage changes, the resistance also changes, and the temperature also changes. It is necessary to detect the temperature of the switching transistor to prevent the situation of component damage due to high temperature;

[0132] When implementing the present invention, considering that too high temperature will damage the circuit, an over-temperature protection module is provided in the current detection circuit. When the switching transistor is in a high-temperature state, the OTP temperature detection voltage signal detects a voltage drop of the switching transistor. When the voltage value exceeds the preset minimum voltage value, the switching transistor is disconnected to perform circuit over-temperature protection. In the boost module, the output voltage of the current acquisition module is boosted to obtain the bias voltage.

[0133] The beneficial effects of the above technical solution are as follows: In the present invention, in order to improve the safety of the current detection circuit, an over-temperature protection module is provided. In the over-temperature protection module, the voltage of the switching transistor can be detected by the OTP temperature detection voltage signal, and the voltage drop can be quickly detected and over-temperature protection is taken.

[0134] As an embodiment of the present technical solution, in the over-temperature protection module, the mobility of the voltage signal of the switching transistor migrating downward is obtained through the OTP temperature detection voltage signal, and the temperature coefficient of the switching transistor is calculated according to the mobility. When the temperature coefficient exceeds the maximum coefficient, circuit over-temperature protection is performed on the current detection circuit;

[0135] Analysis Step 1: Calculate the mobility of the voltage signal of the switching transistor:

[0136]

[0137] where d is the mobility, V d is the voltage mobility of the switching transistor, μ is the current mobility of the switching transistor, W is the switching transistor parameter, T is the switching transistor voltage signal migration time, E is the switching transistor electron energy, and r is the switching transistor resistance;

[0138] Analysis Step 2: Calculate the temperature coefficient of the switching transistor:

[0139]

[0140] where T O represents the time period corresponding to the temperature coefficient of the switching transistor, represents calculating the temperature coefficient of the switching transistor, Q represents the charge quantity of the switching transistor, G represents the conduction rate of the switching transistor, J represents the bandgap energy of the switching transistor, and I represents the bias current of the switching transistor;

[0141] Analysis Step 3: Determine whether over-temperature protection is performed according to the highest temperature coefficient of the switching transistor

[0142]

[0143] where B is the maximum mobility, V B is the maximum voltage mobility of the switching transistor, T B represents the time period corresponding to the maximum temperature coefficient of the switching transistor, represents the maximum temperature coefficient of the switching transistor;

[0144] When the temperature coefficient of the switching transistor exceeds the maximum temperature coefficient of the switching transistor, over-temperature protection is performed on the current detection circuit;

[0145] The working principle of the above technical solution is as follows: In this technical solution, to calculate the highest temperature coefficient of the switching transistor, it is necessary to first calculate the mobility of the voltage signal of the switching transistor. The mobility of the voltage signal of the switching transistor can be calculated by obtaining the current mobility of the switching transistor, the switching transistor parameter, the switching transistor voltage signal migration time, the switching transistor electron energy, and the switching transistor resistance. Then, the temperature coefficient of the switching transistor is calculated through the mobility of the voltage signal of the switching transistor, and it is judged with the highest temperature coefficient of the switching transistor to determine whether the highest temperature coefficient is reached. When the highest temperature coefficient is reached, over-temperature protection is performed on the circuit, and the switching transistor is turned off

[0146] The beneficial effects of the above technical solution are as follows: In the present invention, the mobility of the voltage signal migrated downward by the switching tube is obtained through the OTP temperature detection voltage signal, the temperature coefficient of the switching tube is calculated according to the mobility, and when the temperature coefficient exceeds the maximum coefficient, over-temperature protection is performed on the current detection circuit. By this method, the temperature of the current detection circuit can be monitored in real time, ensuring that when the temperature of the switching tube exceeds the maximum value, over-temperature protection is carried out immediately to avoid circuit damage.

[0147] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) containing computer-usable program code.

[0148] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the specified functions in one process Figure 1 one process or multiple processes and / or blocks Figure 1 or multiple blocks.

[0149] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured product including instruction means, and the instruction means implement the specified functions in one process Figure 1 one process or multiple processes and / or blocks Figure 1 or multiple blocks.

[0150] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation analysis steps are performed on the computer or other programmable device to generate computer-implemented processing, and thus the instructions executed on the computer or other programmable device provide analysis steps for implementing the specified functions in one process Figure 1 one process or multiple processes and / or blocks Figure 1 or multiple blocks.

[0151] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A current detection circuit for a switching circuit, characterized in that, Including: A switching circuit and a current detection circuit; wherein, The input end of the current detection circuit is electrically connected to the drain of the switching transistor of the switching circuit, and the output end of the current detection circuit is electrically connected to the undervoltage lock - up module of the switching circuit; The gate of the switching transistor of the switching circuit is driven by an external PWM signal to control the conduction and disconnection of the switching circuit; The switching circuit includes: a first switching transistor (Q1), a second switching transistor (Q2), a third switching transistor (Q3), an undervoltage lock - up module, and an inductor (L); wherein, The input end of the first switching transistor (Q1) is electrically connected to the power supply, the output end of the first switching transistor (Q1) is electrically connected to the input end of the inductor (L), the output end of the inductor (L) is electrically connected to the input end of the third switching transistor (Q3), the output end of the third switching transistor (Q3) is electrically connected to the input end of the undervoltage lock - up module, and the output end of the second switching transistor (Q2) is grounded; The current detection circuit includes: A switching transistor current acquisition module, which is used to acquire the currents of the first switching transistor (Q1), the second switching transistor (Q2), and the third switching transistor (Q3) to obtain real - time current output values; wherein, the current output values include: a first current output value, a second current output value, and a third current output value; A switching transistor current detection module: used to analyze the current output values through the current data space of the current detection chip to obtain abnormal current output values, and determine the source switching transistor through the abnormal current output values; wherein, The current data space includes: a characteristic point analysis space of current output values, an abnormal current data judgment space, and an abnormal current data source tracking space; A switching transistor current limiting module: used to adjust the current of the switching transistor when the current detection result is not within the preset current threshold.

2. The current detection circuit of a switching circuit according to claim 1, wherein, The switching circuit further includes: a first protection resistor (R1), a second protection resistor (R2), and a third protection resistor (R3); wherein, The gate of the first switching transistor (Q1) is connected to the first protection resistor (R1), and a first PWM driving signal is set at the input end of the first protection resistor (R1); The gate of the second switching transistor (Q2) is connected to the second protection resistor (R2), and a second PWM driving signal is set at the input end of the second protection resistor (R2); The gate of the third switching transistor (Q3) is connected to the protection resistor (R3), and a third PWM driving signal is set at the input end of the third protection resistor (R3).

3. The current detection circuit of a switching circuit according to claim 1, wherein The undervoltage lock - up module includes: A voltage processing unit: used to obtain the output voltage of the switching circuit. When the output voltage is not lower than the output voltage threshold, the undervoltage lock - up module is in a conducting state. When the output voltage is lower than the output voltage threshold, circuit cut - off and locking are performed; A circuit locking unit: used to perform a cut - off output voltage on the switching circuit.

4. The current detection circuit of a switching circuit according to claim 1, characterized in that, The switching transistor current acquisition module further includes: A first switching transistor current acquisition unit: used to generate a first sampling voltage when the current of the first switching transistor (Q1) passes through the sampling resistor, measure the first sampling voltage value, and obtain the first current output value; The second switch transistor current acquisition unit: used to generate a second sampling voltage when the current of the second switch transistor (Q2) passes through the sampling resistor, measure the second sampling voltage value, and obtain the second current output value; The third switch transistor current acquisition unit: used to generate a third sampling voltage when the current of the third switch transistor (Q3) passes through the sampling resistor, measure the third sampling voltage value, and obtain the third current output value.

5. The current detection circuit of a switching circuit according to claim 1, characterized in that The current detection circuit further includes: The switch transistor current protection module: used to control the drain voltages of the first switch transistor (Q1), the second switch transistor (Q2), and the third switch transistor (Q3) through an operational amplifier to obtain stable drain voltage values.

6. The current detection circuit of a switching circuit according to claim 1, wherein, The switch transistor current detection module further includes: The current analysis unit: used to set a current analysis program in the current detection chip; wherein the analysis steps of the analysis program are: Analysis step one: Analyze the real-time acquired current output values through a preset current data space, and analyze the current output values through the data signal characteristics of the current data space; Analysis step two: Judge whether each current output value is within a preset error tolerance range. When the characteristic points of the current output value are within the preset error tolerance range, classify the current output value as normal data. Analysis step three: When the current output value is not within the preset error tolerance range, classify the current output value as abnormal data; The detection abnormal unit: used to determine the switch transistor of the abnormal data according to the abnormal data.

7. The current detection circuit of a switching circuit according to claim 1, characterized in that The switch transistor current limiting module further includes: The switch transistor overcurrent unit: used to make the switch transistor enter the saturation region when the current value of the switch transistor is overcurrent, charge the soft start capacitor of the operational amplifier, and consume the excess current; The switch transistor low current unit: used to make the switch transistor enter the non-saturation region when the current value of the switch transistor is lower than the standard current value, discharge the soft start capacitor of the operational amplifier, and increase the current of the switch transistor.

8. The current detection circuit of a switching circuit according to claim 1, characterized in that, The current detection circuit further includes: The overtemperature protection module: used to detect whether the switch transistor is in a high temperature state through the OTP temperature detection voltage signal. When the temperature of the switch transistor exceeds the temperature threshold, the OTP temperature detection voltage signal detects a voltage drop of the switch transistor. When the voltage value exceeds the preset minimum voltage value, perform circuit overtemperature protection and disconnect the switch transistor; The boost module: used to accurately boost the voltage signal of the current acquisition module, boost the output voltage of the current acquisition module through the first boost circuit, and obtain the bias voltage.

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